1. Field of the Invention
The invention relates to a diesel filter provided in a fuel supply system of a vehicle and the like, particularly to a diesel filter that enables replacement of elements and the like without removing a fixed portion of a vehicle body and the like.
2. Description of the Related Art
Diesel engines have long been used as engines for vehicles and the like. In a diesel engine, a diesel filter filters light oil in a fuel tank, and an injection pump compresses the filtered fuel to a high pressure, and an injector injects the fuel to a combustion chamber of the engine so that the fuel is burned in the combustion chamber.
Incidentally, fuel includes foreign matters, for example, water, dust, and solid undesirable materials such as rust. These foreign matters need to be removed because inclusion thereof results in reduced combustion efficiency and wear of the injector or the like. Diesel filters are, therefore, provided to deal with such problems. More specifically, water content in fuel includes dissolved water and free water. Dissolved water causes no negative effects, because it flows smoothly in fuel channels and is consumed together with fuel. Meanwhile, free water may cause some problems as follows. Free water appears in fuel when: rainwater intrudes into the fuel during fueling; water droplets formed by moisture in the air intrude into the fuel; or the water dissolved in the fuel is separated therefrom due to a decrease in fuel temperature. Such free water is large in specific gravity compared to light oil, so that it stagnates in the injection pump and the like, thus generating rust and stick. For this reason, free water particularly needs to be removed using a diesel filter.
A diesel filter related to the invention will be described. A diesel filter includes a cup-shaped case forming an outer shell, and a cap detachably attached to an upper open end of the case.
The cap is provided with a fuel supply pipe and a fuel discharge pipe, through which fuel is supplied and discharged. Integrally formed with the top surface of the cap is a bracket for fixing the diesel filter to a predetermined portion of a vehicle body. By attaching attachment parts, such as fasteners, to attachment holes formed in the bracket, the diesel filter is fixed to the predetermined portion of the vehicle body.
Housed in the case is a filter member that includes an element having a fuel passage at the center thereof, and an upper and lower holding members for holding the upper and lower ends of the element. A water reservoir is formed below the filter member.
Fuel is introduced into the water reservoir through the fuel supply pipe and the fuel passage. In the water reservoir, free water contained in the fuel is separated from the fuel. Then, the fuel reverses its direction and moves upward, and passes through the element, so that foreign matter contained in the fuel is removed. The fuel free from foreign matter is then discharged from the fuel discharge pipe. The separated water has a larger specific gravity than the fuel, therefore the water is retained in the water reservoir. When the volume of the retained water reaches a predetermined value or more, a drain cock is opened to discharge the water. As described above, the diesel filter is provided with the water reservoir at a lower portion thereof, so that the diesel filter is fixed to the predetermined portion of the vehicle body in an upright manner. Other parts are provided around and below the diesel filter (see Japanese Patent Application Publication No. JP-A-7-208292) so as to be closely adjacent.
Note that the diesel filter needs to be replaced after a predetermined period of time because of clogging of the element. As described above, the diesel filter 1 is surrounded by the other parts arranged around and below the diesel filter. Therefore, when replacing the element with a new one, the bracket is first detached from the vehicle body, and the diesel filter is then pulled up to be removed from where it was installed. The removed diesel filter is then disassembled for replacing the element. In this manner, replacing the element inevitably involves disassembly, which has been a problem.
When the diesel filter includes a level detector for detecting the volume of water in the water reservoir, a wiring member including a harness, a connector, or the like, to which the level detector is connected, is normally attached to the cap or to a particular portion in the vehicle body side. In this case, the wiring member, e.g., a connector, needs to be removed from the cap or the portion in the vehicle body side before removing the bracket 6 from the vehicle body. Accordingly, the number of man-hours required for the replacement work increases, resulting in poor workability.